Sage 100 was first introduced as MAS 90 (Master Accounting Series for the 90’s) in the mid-1980s by a company called State of the Art, Inc. located in Irvine, CA.
The Sage Group PLC purchased State of The Art in 1998 and shortly thereafter renamed MAS 90 to Sage 100 (perpetual licensing) and now to Sage 100cloud (subscription licensing).
According to this 2018 external roadmap posted in February 2018 by Sage, there are 24,600+ customers of Sage 100 and Sage 100cloud. Subsequently in January 2020 Sage announced an updated customer count of 30,000+ Sage 100 customers. In April 2021 Sage somewhat narrowed their customer count to “15,000+ active customers” as shown below.
April 2021 What’s New in Sage 100 2021 displayed a more ambiguous customer count of 14,000+ active customers.
The discrepancy in user counts from year to year are likely a change in how the customers were measured ( actual users vs users on maintenance vs total number of companies setup in Sage , etc ).